Process of manufacturing celluloid-like masses



Patented Aug. 11, 1931 UNITED STATES PATENT OFFICE.

MAX JOSEPH THEUMANN, OF LYON, FRANCE, ASSIGNOB, MESNE ASSIGNMENTS, r

E. I. DU 'I'ONT DE NEMOURS AND COMPANY, 01 WILMINGTON, DELAWARE, A COR- PORATION OF DELAWARE PROCESS 0] MANUFACTURING CELLULOID-LIKE MASSES No Drawing. Application filed July 8, 1926, Serial No. 120,586, and in Germany July 14, 1925.

This invention relates to a process of manufacturing a celluloid-like product, by the use of an acetone-soluble acetyl cellulose, the object of the invention being to provide a proc- 5 ess by means of which the-solvent mamtams its original dissolving property throughout the operation.

If one tries to produce plastic celluloidlike masses from an acetone-soluble acetyl m cellulose, by treatement with the mixture of ethyl alcohol and benzol suggested by Elohengriin (U. S. Patent No. 1,015,155) for the solution of the acetyl cellulose, it will be noted that the acetyl cellulose remains in solution only in the presence of heat and that t quickly separates out upon cooling off. This act was ascertained by Eichengriin, and it was the precipitated mass which was used by him for the preparation of celluloid. It

is true that Eichengriin states that this separation can be avoided by the addition of acetone. However, he did not use the solutions thus obtained for the production of celluloid, as the gelatinization, which is prevented by the addition of the acetone, seemed to him of particular value for this purpose.

With the present invention the difiiculties which heretofore revented the use of these solutions are avoided and celluloid is obtained of excellent quality. By treating the acetone-soluble acetyl cellulose with a mixture of acetone, benzol and fatty alcohol especially good results are obtained, if the proportion of materials isso selected that the volatile mixture retains its original solvent properties throughout the whole process. If this precaution is not taken however, the individual components evaporating at unequal speeds, the mixture which originally was capable of dissolving the acetyle cellulose loses this property. Consequently the acetyl cellulose finds itself in the presence of a volatile mixture lacking the required solvent capacity, which renders more diflicult the making of the celluloid and particularly the molding thereof. The preparation of the celluloid is even rendered impossible if it is a question of a complicated structure, or if it is desired to produce a celluloid with a high acetate content. In every case the resulting product is of a very inferior grade, as the mass is not uniform and the separate layers do not unite very well. The invention is particularly a phcable to an acetone-soluble acetyl ce ulose, (which, however, is insoluble in ethyl acetate) which is, according to the experiments of the ap- Example 1 Knead 7 5 kilos of acetyl cellulose soluble in acetone but practically insoluble in ethyl acetate, with 50 kilos of a mixture consisting of:

- 33 parts by weight of acetone 52 parts by weight of benzol 14 parts by weight of ethyl alcohol and add 2 5 kilos of a caniphor substitute 124 In this way one obtains quickly a transparent mass which can be filtered, rolled, pressed into blocks and cut.

Emample 2 Knead 75 kilos of acetyl cellulose soluble in acetone but practicall insoluble in ethyl acetate, with 50 kilos o a mixture consisting of:

48 parts by weight of acetone 32 parts by wei ht of benzol 20 parts by we ght of methyl alcohol 25 kilos of a camphor substitute.

This mass'is worked as stated under Example 1.

In these examples the quantity of the camphor substitute may be varied without in any way impairing the uniformity of the mass. In this way more or less hard products are obtained.

Having thus described my invention, what I claim is:

and add 1. A recess for the preparation of a celluloide mass from an acetone-soluble acetyl cellulose practically insoluble in ethyl acetate, which consists in treating the acetyl cellulose with a solvent mixture containing 33 to 48 parts by weight of acetone, 32 to 52 pfrts by weight of benzol and 14 to 20 parts y weight of an alcohol, the relatlve proportions y wei ht of acetyl cellulose and solvent mixture ing approximately 75 and 50.

2. A rocess for the preparation of a celluloide mass from an acetone-soluble acetyl cellulose practicall insoluble in ethyl acetate, which consists 111 treating the acetyl cellulose with a solvent mixture containing 33 'to 48 parts by weight of acetone, 32 to 52 arts by wei ht of benzol and 14 to 20 parts y weight 0 an alcohol, the relative proportions by wei ht of acetyl celluloseand solvent mixture ing ap roximately 75 and 50,

the whole being mixe with a camphor sub stitute. v

In testimony whereof I have signed my name to this ification.

mOSEPH THEUMANN. 

